1. Field of the Invention
The present invention relates to exposure apparatuses, and more particularly to an exposure apparatus that exposes an object with an energy beam and forms a pattern on the object.
2. Description of the Background Art
In a lithography process on manufacturing electronic devices (microdevices) such as semiconductor devices and liquid crystal display devices, exposure apparatuses such as a projection exposure apparatus by a step-and-repeat method (a so-called stepper) or a projection exposure apparatus by a step-and-scan method (a so-called scanning stepper (which is also called a scanner) are relatively frequently used.
Meanwhile, because a semiconductor device or the like is formed by overlaying many layers of circuit patterns on a substrate (such as a wafer or a glass plate), it is important that the overlay accuracy between the respective layers is favorable. For example, in the case of the scanner, in order to improve the overlay accuracy, it is important to improve synchronous accuracy between a mask stage holding a mask and a substrate stage holding a substrate.
However, even if the synchronous accuracy between the mask stage and the substrate stage is favorable, it is difficult to improve the overlay accuracy when vibration is propagated from the outside to a projection optical system. Therefore, also in conventional methods, in order to improve position controllability of both the stages and also to suppress the propagation of vibration to the projection optical system, a holding member that holds the projection optical system was supported via a vibration isolation device on a base member installed on a floor surface. Further, recently, in order to preclude the vibration propagated to the projection optical system or the like, an exposure apparatus in which the projection optical system is held by suspension from a body (column) has been proposed (e.g. refer to Kokai (Japanese Unexamined Patent Application Publication) No. 2007-005669).
In this manner, in an exposure apparatus, the holding member that holds a projection optical system and a body that is installed on a floor surface are separated in terms of vibration using a vibration isolation device or the like, but recently the vibration-wise separation of the holding member and the body as is described above has been no longer sufficient, due to finer patterns accompanying higher-integration of semiconductor devices. That is, even if the holding member and the body are separated, as long as wiring for electric power supply or for signal transmission, or piping for coolant supply or the like exists between the holding member and the body, fine vibration from the floor surface is propagated to the projection optical system through the wiring or the piping, and even such fine vibration cannot be ignored now.